In a known vehicle body structure, the front end of a floor tunnel is joined to a dash lower panel from the side of a vehicle cabin, an upper part of the front end of the floor tunnel is connected to a dash cross member by a connecting member, and the dash cross member extends in a vehicle-body width direction.
Furthermore, the dash cross member extending in the vehicle-body width direction bridges a left front pillar and a right front pillar, and the lower end at the front end of the floor tunnel is connected to a floor frame (see Japanese Patent No. 4483592, for example).
If the vehicle body structure according to Japanese Patent No. 4483592 encounters an accident with front collision and a power source (for example, an engine) provided in its engine room is moved toward the vehicle-body rear side and bumps against the dash cross member, a load is applied to the dash cross member horizontally toward the vehicle-body rear side.
The load applied to the dash cross member is transmitted through the connecting member to the upper part of the front end of the floor tunnel and then, along sidewalls of the floor tunnel, to the lower end of the floor tunnel. That is, the horizontally acting load applied to the dash cross member is converted into a load acting downward and outward in the vehicle-body width direction.
Furthermore, the load transmitted to the lower end of the floor tunnel is transmitted along the floor frame toward the vehicle-body rear side. That is, the load acting downward and outward in the vehicle-body width direction and reaching the lower end of the floor tunnel is converted into a load acting horizontally toward the vehicle-body rear side.
Thus, a load applied to the dash cross member is transmitted to and borne by the connecting member, the floor tunnel, and the floor frame, whereby the deformation of the dash lower panel is suppressed.
In the vehicle body structure according to Japanese Patent No. 4483592, a load applied to the dash cross member is converted into a load acting downward and outward in the vehicle-body width direction, and the load having reached the lower end of the floor tunnel is further converted into a load acting horizontally toward the vehicle-body rear side.
Hence, considering the bending moment occurring in a portion where the load is redirected, the size of the portion where the load is redirected needs to be increased. Such a situation makes it difficult to suppress the increase in the weight of the vehicle body structure. In this respect, there is still room for improvement.